Field of the Invention
The invention is directed to an image processing technique and more particularly, an image processing method and a display device thereof capable of extending a lifetime of a display panel.
Description of Related Art
A solid state light source (e.g., a light-emitting diode (LED), an organic light-emitting diode (OLED), etc.), in comparison with a fluorescent lamp or an incandescent lamp of the related art, has advantages, such as small volume, long lifetime, high reliability and so on, thus, has become the focus of development of the optoelectronic industry and widely applied in the lighting market and display devices in a variety of sizes. The OLED is self-luminous and does not need any backlight source, such that an OLED film has a thin characteristic to achieve light transparency and a better development vision than the LED.
As an OLED element is used for a long time, or driven by high luminance, material deterioration occurs to the OLED element, which leads to reduced emitting efficiency, decreased life cycle of a display panel, and occurrence of defects, such as image sticking, on the display panel. According to an experiment, the lifetime of the OLED element relates to a current amount (which is referred to as current density herein) of an emitting area per unit. For example, when the OLED element is driven by a current density of 10 mA/cm2, an average light-emitting intensity of the OLED element will become half of an original light-emitting intensity after about 40000 hours. When the OLED element is driven by a current density of 20 mA/cm2, the average light-emitting intensity of the OLED element will become half of an original light-emitting intensity after about 20000 hours. Namely, as the current density increases, a non-linear drop will appear in a relation graph of the average light-emitting intensity of the OLED element with respect to time. Additionally, recent displays tends to be provided with high resolution to present delicate images. As a result, a light-emitting area of the OLED element for presenting each pixel is gradually reduced, such that the current density of the OLED element is increased, which also leads to reduction of the lifetime of the OLED element.
Accordingly, how to mitigate the decay speed of the solid state light source, so as to increase the lifespan of the display panel has become a goal of technological progress in the solid state light source to be achieved by manufacturers.